CA2399724C - Glass/polyvinylbutyral laminates having directional surface patterns and a process for preparing same - Google Patents
Glass/polyvinylbutyral laminates having directional surface patterns and a process for preparing same Download PDFInfo
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- CA2399724C CA2399724C CA2399724A CA2399724A CA2399724C CA 2399724 C CA2399724 C CA 2399724C CA 2399724 A CA2399724 A CA 2399724A CA 2399724 A CA2399724 A CA 2399724A CA 2399724 C CA2399724 C CA 2399724C
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- Prior art keywords
- pattern
- sheet
- polyvinyl butyral
- glass
- laminate
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
- B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
- B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
- B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
- B32B17/1055—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the resin layer, i.e. interlayer
- B32B17/10761—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the resin layer, i.e. interlayer containing vinyl acetal
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
- B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
- B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
- B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
- B32B17/1055—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the resin layer, i.e. interlayer
- B32B17/10559—Shape of the cross-section
- B32B17/10577—Surface roughness
- B32B17/10596—Surface roughness created by melt fracture
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/001—Combinations of extrusion moulding with other shaping operations
- B29C48/0021—Combinations of extrusion moulding with other shaping operations combined with joining, lining or laminating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/07—Flat, e.g. panels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/07—Flat, e.g. panels
- B29C48/08—Flat, e.g. panels flexible, e.g. films
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0037—Other properties
- B29K2995/0072—Roughness, e.g. anti-slip
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31551—Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
- Y10T428/31627—Next to aldehyde or ketone condensation product
- Y10T428/3163—Next to acetal of polymerized unsaturated alcohol [e.g., formal butyral, etc.]
Landscapes
- Joining Of Glass To Other Materials (AREA)
- Laminated Bodies (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
De-airing of PVB/glass laminates can be improved, while haze in the pre-press is minimized and sleep time reduced as a result using a PVB sheet having a roughened surface with directionality. A roughened surface with a washboard pattern that is useful in this regard can be obtained by varying certain conditions of a melt-fracture extrusion process.
Description
TITLE
GLASS/POLYVINYLBUTYRAL LAMINATES HAVING DIRECTIONAL
SURFACE PATTERNS AND A PROCESS FOR PREPARING SAME
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to glass laminates. The present invention particularly relates to laminates of glass and polyvinylbutyral, and a process of preparing same.
Description of Related Art Glass laminates that include plasticized polyvinyl butyral (PVB) interlayers can be used in various applications, including use in automotive safety glass applications such as windshields and side glass; in architectural applications such as windows, doors and/or building panels; and in various other applications such as in display cases, as shelving, and the like.
Glass/PVB laminates can be prepared by conventional methods. Typically, a laminate can be prepared by first positioning a sheet of PVB between two pieces of glass to obtain an assembly, and trimming the excess of PVB interlayer. A "pre-press"
is obtained from the assembly by removing air trapped between the glass and the interlayer, and then sealing the edges. A conventional method for edge sealing requires placing the assembly inside of a rubber bag and removing the air from the bag by applying vacuum.
The rubber bag and contents can then be passed through a furnace wherein the temperature is increased to about 135 C in order to obtain the pre-press. A pre-press so obtained can be heated in an autoclave wherein heat and pressure are applied, residual air is dissolved in the PVB interlayer, and bonding occurs between the interlayer and the surface being laminated.
An interlayer having a smooth surface can present problems during the assembly and de-airing steps of a lamination process if a vacuum bag system is used to make the pre-press. In the assembly step, the smooth pattern allows the interlayer to tack too easily to the glass, making placement of the interlayer difficult. In the de-airing step, a smooth pattern can lead to a laminate having trapped air, and flaws in the laminate can result therefrom. It is known that interlayers having a rough surface can facilitate de-airing. Rough surface patterns can be generated by conventional methods, including use of an embossing tool to impart a reproducible pattern on the surface of the interlayer material. It is also conventional to generate a randomly irregular surface pattern by a melt-fracture process, which can provide channels by which air can escape during the lamination process.
In a typical windshield laminating process, the PVB interlayer is first subjected to a shaping step wherein the PVB interlayer is differentially stretched such that the shaped interlayer better conforms to the curvature of the vehicle for which the windshield is designed. In the shaping step, the PVB roll is unwound, and the interlayer is heated to approximately 100 C and then passed over one or more cones which are smooth, and then chilled to approximately 10 C for storage, and then cut into blanks slightly larger than the size of the windshield.
Stresses incurred in the shaping process are partially relaxed as the blanks are conditioned at 10 C. During the shaping step, some of the pattern roughness is pressed out temporarily, but will recover according to stress relaxation kinetics well known in the art of polymer theology.
For interlayers with surface patterns generated in a melt-fracture process, haze in a pre-press can be a problem, especially if the interlayer material is used within twelve hours of being shaped for lamination in a vacuum bag pre-pressing system. Pre-presses with less than 15% light transmission are typically rejected.
Use of an embossing tool can be effective in resolving the de-airing and pre-press clarity concerns, but is more costly and more work intensive than use of a melt fracture process. An embossing process is inflexible relative to the melt fracture process, with respect to producing different patterns on the same equipment.
While use of rough patterns obtained by a melt-fracture process could improve the effectiveness of de-airing by vacuum, rough patterns generated by melt facture require more energy to melt down in the heating step. This could render the pre-press hazier than if it had been made from a smoother interlayer. In a conventional process for making flat laminates, a glass/PVB/glass assembly is typically heated to the point where the PVB
attains a temperature of about 50-90 C. At this temperature, the entire assembly is passed through a set of nip rolls, and the nip rolls exert pressure that squeezes out the interstitial air and also seals the edges of the pre-press. Pre-presses that use conventional PVB with a roughened surface obtained by a melt fracture process tend to be hazy if RZ is above 30 micrometers.
It is desirable to obtain an interlayer material with a surface rough enough to minimize haze in a pre-press, yet maintain a desirable balance of physical properties of the interlayer, without requiring the capital investment, loss of yield, loss of flexibility, or possible contamination that can result from use of an embossing tool. Therefore it can be desirable to obtain such a rough surface without the use of an embossing tool.
SUMMARY OF THE INVENTION
In one aspect the present invention is a plasticized polyvinyl butyral sheet having a directional surface pattern created using a melt fracture process during extrusion of the sheet.
In another aspect, the present invention is a plasticized polyvinyl butyral sheet having a washboard surface pattern created using a melt fracture process during extrusion of the sheet.
In another aspect, the present invention is a plasticized polyvinyl butyral sheet having a herringbone surface pattern created using a melt fracture process during extrusion of the sheet.
According to a particular embodiment, the invention provides a polyvinyl butyral sheet having a roughened directional surface pattern obtained by a melt fracture extrusion process without the use of an embossing tool, wherein the roughened directional surface pattern is a herringbone pattern obtained by using a die pressure of less than 37 kg/cm2.
According to preferred aspects, the sheet has an RZ of greater than 35, or greater than 30, or the RZ may be in a range of from 15 to 35, or from 20 to 30.
GLASS/POLYVINYLBUTYRAL LAMINATES HAVING DIRECTIONAL
SURFACE PATTERNS AND A PROCESS FOR PREPARING SAME
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to glass laminates. The present invention particularly relates to laminates of glass and polyvinylbutyral, and a process of preparing same.
Description of Related Art Glass laminates that include plasticized polyvinyl butyral (PVB) interlayers can be used in various applications, including use in automotive safety glass applications such as windshields and side glass; in architectural applications such as windows, doors and/or building panels; and in various other applications such as in display cases, as shelving, and the like.
Glass/PVB laminates can be prepared by conventional methods. Typically, a laminate can be prepared by first positioning a sheet of PVB between two pieces of glass to obtain an assembly, and trimming the excess of PVB interlayer. A "pre-press"
is obtained from the assembly by removing air trapped between the glass and the interlayer, and then sealing the edges. A conventional method for edge sealing requires placing the assembly inside of a rubber bag and removing the air from the bag by applying vacuum.
The rubber bag and contents can then be passed through a furnace wherein the temperature is increased to about 135 C in order to obtain the pre-press. A pre-press so obtained can be heated in an autoclave wherein heat and pressure are applied, residual air is dissolved in the PVB interlayer, and bonding occurs between the interlayer and the surface being laminated.
An interlayer having a smooth surface can present problems during the assembly and de-airing steps of a lamination process if a vacuum bag system is used to make the pre-press. In the assembly step, the smooth pattern allows the interlayer to tack too easily to the glass, making placement of the interlayer difficult. In the de-airing step, a smooth pattern can lead to a laminate having trapped air, and flaws in the laminate can result therefrom. It is known that interlayers having a rough surface can facilitate de-airing. Rough surface patterns can be generated by conventional methods, including use of an embossing tool to impart a reproducible pattern on the surface of the interlayer material. It is also conventional to generate a randomly irregular surface pattern by a melt-fracture process, which can provide channels by which air can escape during the lamination process.
In a typical windshield laminating process, the PVB interlayer is first subjected to a shaping step wherein the PVB interlayer is differentially stretched such that the shaped interlayer better conforms to the curvature of the vehicle for which the windshield is designed. In the shaping step, the PVB roll is unwound, and the interlayer is heated to approximately 100 C and then passed over one or more cones which are smooth, and then chilled to approximately 10 C for storage, and then cut into blanks slightly larger than the size of the windshield.
Stresses incurred in the shaping process are partially relaxed as the blanks are conditioned at 10 C. During the shaping step, some of the pattern roughness is pressed out temporarily, but will recover according to stress relaxation kinetics well known in the art of polymer theology.
For interlayers with surface patterns generated in a melt-fracture process, haze in a pre-press can be a problem, especially if the interlayer material is used within twelve hours of being shaped for lamination in a vacuum bag pre-pressing system. Pre-presses with less than 15% light transmission are typically rejected.
Use of an embossing tool can be effective in resolving the de-airing and pre-press clarity concerns, but is more costly and more work intensive than use of a melt fracture process. An embossing process is inflexible relative to the melt fracture process, with respect to producing different patterns on the same equipment.
While use of rough patterns obtained by a melt-fracture process could improve the effectiveness of de-airing by vacuum, rough patterns generated by melt facture require more energy to melt down in the heating step. This could render the pre-press hazier than if it had been made from a smoother interlayer. In a conventional process for making flat laminates, a glass/PVB/glass assembly is typically heated to the point where the PVB
attains a temperature of about 50-90 C. At this temperature, the entire assembly is passed through a set of nip rolls, and the nip rolls exert pressure that squeezes out the interstitial air and also seals the edges of the pre-press. Pre-presses that use conventional PVB with a roughened surface obtained by a melt fracture process tend to be hazy if RZ is above 30 micrometers.
It is desirable to obtain an interlayer material with a surface rough enough to minimize haze in a pre-press, yet maintain a desirable balance of physical properties of the interlayer, without requiring the capital investment, loss of yield, loss of flexibility, or possible contamination that can result from use of an embossing tool. Therefore it can be desirable to obtain such a rough surface without the use of an embossing tool.
SUMMARY OF THE INVENTION
In one aspect the present invention is a plasticized polyvinyl butyral sheet having a directional surface pattern created using a melt fracture process during extrusion of the sheet.
In another aspect, the present invention is a plasticized polyvinyl butyral sheet having a washboard surface pattern created using a melt fracture process during extrusion of the sheet.
In another aspect, the present invention is a plasticized polyvinyl butyral sheet having a herringbone surface pattern created using a melt fracture process during extrusion of the sheet.
According to a particular embodiment, the invention provides a polyvinyl butyral sheet having a roughened directional surface pattern obtained by a melt fracture extrusion process without the use of an embossing tool, wherein the roughened directional surface pattern is a herringbone pattern obtained by using a die pressure of less than 37 kg/cm2.
According to preferred aspects, the sheet has an RZ of greater than 35, or greater than 30, or the RZ may be in a range of from 15 to 35, or from 20 to 30.
In another aspect, the present invention is a process for creating a directional pattern on a surface of a plasticized polyvinyl butyral sheet using a melt fracture process during extrusion of the sheet.
According to a particular embodiment the process for creating a directional pattern on a surface of a polyvinyl butyral sheet includes the step of extruding molten polyvinyl butyral using a melt fracture extrusion process. The pattern can be varied by varying the extrusion process parameters and an embossing tool is not used. The directional pattern is a herringbone pattern or washboard pattern. The washboard pattern is created using a die pressure of greater than 58 kg/cm2. The herringbone pattern is created using a die pressure of less than 37 kg/cm2.
The process, according to a particular aspect, includes use of a lip steam pressure that is below 15 kg/cm2 (1.47 MPa) for the creation of the herringbone pattern.
In still another aspect, the present invention is a laminate comprising a plasticized polyvinyl butyral interlayer, wherein the interlayer is obtained from a polyvinyl butyral sheet having a directional surface pattern created using a melt fracture process during extrusion of the sheet.
According to a particular embodiment, the laminate comprises a polyvinyl butyral interlayer, wherein the interlayer is obtained from a polyvinyl butyral sheet having a roughened directional surface pattern obtained by extrusion of the sheet using a melt fracture process, wherein the roughened directional surface pattern is a herringbone pattern in which the herringbone pattern is obtained by using a die pressure of less than 37 kg/cm2.
The laminate can have at least one layer that is glass in which the glass is adhered to the polyvinyl butyral sheet.
The polyvinyl butyral sheet of the laminate can also be adhered to at least two layers of glass.
A laminate of the invention can include at least one layer of an additional polymer in addition to the polyvinyl butyral sheet.
The invention includes use of a laminate of the invention in the manufacture of an article.
The article can be a windshield, automotive side-glass, a window, shelf, or architectural glass, and the invention includes use of any of these.
According to another aspect, the invention is polyvinyl butyral for use in the manufacture of a polyvinyl butyral sheet for use in a laminate of the invention.
/ ...4a The invention also includes use of polyvinyl butyral in the manufacture of a polyvinyl butyral sheet for use in a laminate, the sheet having a roughened directional surface pattern wherein the surface pattern is obtained by extrusion of the sheet using a melt fracture process, wherein the roughened directional surface pattern is a herringbone pattern obtained by using a die pressure of less than 37 kg/cm2.
The invention also include use of a polyvinyl butyral sheet of the invention as an interlayer of a laminate.
DETAILED DESCRIPTION
In one embodiment, the present invention is a plasticized polyvinyl butyral (PVB) sheet having a roughened surface wherein the surface has directionality imparted by a melt fracture extrusion process. PVB sheeting of the present invention is plasticized. Conventional plasticizers known in the art of preparing PVB sheets can be used in the practice of the present invention. Such plasticizers include, but are not limited to: triethylene glycol-di-2-ethyl butyrate; triethylene glycol-di-2-ethyl hexanoate; and dibutyl sebacate.
The roughness of the surface of a PVB sheet of the present invention is such that haze in a glass/PVB pre-press is low even if the PVB is used within 12 hours after it is stretched.
Surface roughness can be measured by conventional methods, and can be expressed by the term Rz. In a washboard PVB sheet of the present invention RZ is greater than about 30 micrometers, as determined by ISO R468. Preferably a washboard pattern of the present invention has a roughness of greater than about 35, more preferably greater than about 40 and most preferably from about 35 to about 100. In a herringbone pattern of the present invention, the RZ is less than about 35, preferably less than about 30, more preferably from about 15 to about 35, and most preferably from about 20 to about 30 micrometers. In a PVB
sheet of the present invention, the rough surface has a directional pattern, and the rough directional pattern is obtained without use of an embossing tool.
In another embodiment, the present invention is a laminate comprising at least one layer of PVB and at least one layer of glass, wherein the PVB layer is obtained by an extrusion process wherein a roughened PVB surface having / ...5 4a directionality is obtained without use of an embossing tool. The laminate is prepared according to conventional methods, wherein an assembly comprising at least one layer of PVB of the present invention is heated, and then de-aired under vacuum and at elevated temperature to form a pre-press. Alternatively, the laminate can be prepared by heating the assembly in an oven and then passing it through one or more pairs of nip rolls. The pre-press can be autoclaved according to conventional methods and conditions to yield a finished laminate article.
In still another embodiment, the present invention is a process for preparing a PVB sheet having a roughened surface having directionality imparted using a melt fracture extrusion process, without the aid of an embossing'tool.
The process comprises varying certain conditions and parameters in the extrusion process of PVB sheeting material. To prepare conventional PVB sheeting material, typically parameters can be varied to control surface pattern. Some parameters that can be varied are die body temperature and die gap, sheet caliper, lip stream pressure, lip gap, air gap, content of plasticizer, temperature of polymer, throughput of molten polymer per unit die width, and temperature of quench water. Other parameters can be varied as well. The directional patterns of the present invention can be obtained in the process of the present invention by varying the die pressure. Under certain die pressure operating conditions, a washboard pattern is one type of directional pattern that can be obtained on the PVB surface. For example, a washboard pattern can be obtained by operating at a die pressure of greater than 58 kg/ cm2 (5.69 MPa). A washboard pattern or surface, as the term is used herein, describes a surface having alternately high (1) and low (2) areas of elevation that form ridges (3), similar to the surface of a washboard. The ridges on a PVB surface of the present invention are nearly parallel to the cross-web direction of the interlayer as it is extruded, the cross-web direction being the direction perpendicular to that of the extrusion. Under certain other conditions of die pressure, a herringbone pattern can be obtained on the PVB
surface. A herringbone pattern is a second type of directional surface pattern that can be obtained in the process of the present invention by varying process conditions. For example, a herringbone pattern can be obtained by varying die pressure such that the pressure is below 37 kg/cm2 (3.63 MPa). The herringbone and washboard patterns are shown in Figure 1 and Figure 2, respectively. Other patterns can be obtained by varying process conditions, but the directional patterns of the present invention are controlled primarily by the die pressure.
Throughput (rate of polymer through the die)can be in the range of from about 600 to about 1000 kg per hr per meter, depending on the equipment being used.
EXAMPLES
The Examples and comparative examples herein are included for illustrative purposes only, and are not intended to limit the scope of the present invention.
In Examples 1-25, 100 parts of dry PVB flake of nominally 18-23% by weight of un-butyralated vinyl alcohol groups were mixed with 35-40 parts of tetraethylene glycol di-n-heptanoate plasticizer and one or more light stabilizers marketed under the tradename " Tinuvin" by Ciba-Geigy Co. and an antioxidant which were pre-mixed in the plasticizer continuously in a twin-screw extruder. The melt was forced through a slot die and formed a sheeting of 0.76 mm nominal thickness.
In addition, agents for modifying surface energy of the bulk interlayer and usual adjuvants such as antioxidants, colorants and ultraviolet absorbers which do not.
adversely affect the functioning of the surface energy modifying agent and adhesion control agent can be included in the PVB composition. The melt at the die is at approximately 200-220 C. The lips of the die are heated by injecting pressurized steam into cavities therein. The lip temperature is controlled by the pressure of the steam injected. One of the die lips is adjustable so that as it opens, the back-pressure in the die is decreased and vice versa. The position of this lip is computer-controlled, and a desired back-pressure in the die (die pressure) is used as input.
PVB sheeting having washboard or herringbone pattern was prepared on conventional extrusion equipment by varying the condition of die pressure. The same equipment was used for all of the examples. The conditions and results are given in the Table below.
According to a particular embodiment the process for creating a directional pattern on a surface of a polyvinyl butyral sheet includes the step of extruding molten polyvinyl butyral using a melt fracture extrusion process. The pattern can be varied by varying the extrusion process parameters and an embossing tool is not used. The directional pattern is a herringbone pattern or washboard pattern. The washboard pattern is created using a die pressure of greater than 58 kg/cm2. The herringbone pattern is created using a die pressure of less than 37 kg/cm2.
The process, according to a particular aspect, includes use of a lip steam pressure that is below 15 kg/cm2 (1.47 MPa) for the creation of the herringbone pattern.
In still another aspect, the present invention is a laminate comprising a plasticized polyvinyl butyral interlayer, wherein the interlayer is obtained from a polyvinyl butyral sheet having a directional surface pattern created using a melt fracture process during extrusion of the sheet.
According to a particular embodiment, the laminate comprises a polyvinyl butyral interlayer, wherein the interlayer is obtained from a polyvinyl butyral sheet having a roughened directional surface pattern obtained by extrusion of the sheet using a melt fracture process, wherein the roughened directional surface pattern is a herringbone pattern in which the herringbone pattern is obtained by using a die pressure of less than 37 kg/cm2.
The laminate can have at least one layer that is glass in which the glass is adhered to the polyvinyl butyral sheet.
The polyvinyl butyral sheet of the laminate can also be adhered to at least two layers of glass.
A laminate of the invention can include at least one layer of an additional polymer in addition to the polyvinyl butyral sheet.
The invention includes use of a laminate of the invention in the manufacture of an article.
The article can be a windshield, automotive side-glass, a window, shelf, or architectural glass, and the invention includes use of any of these.
According to another aspect, the invention is polyvinyl butyral for use in the manufacture of a polyvinyl butyral sheet for use in a laminate of the invention.
/ ...4a The invention also includes use of polyvinyl butyral in the manufacture of a polyvinyl butyral sheet for use in a laminate, the sheet having a roughened directional surface pattern wherein the surface pattern is obtained by extrusion of the sheet using a melt fracture process, wherein the roughened directional surface pattern is a herringbone pattern obtained by using a die pressure of less than 37 kg/cm2.
The invention also include use of a polyvinyl butyral sheet of the invention as an interlayer of a laminate.
DETAILED DESCRIPTION
In one embodiment, the present invention is a plasticized polyvinyl butyral (PVB) sheet having a roughened surface wherein the surface has directionality imparted by a melt fracture extrusion process. PVB sheeting of the present invention is plasticized. Conventional plasticizers known in the art of preparing PVB sheets can be used in the practice of the present invention. Such plasticizers include, but are not limited to: triethylene glycol-di-2-ethyl butyrate; triethylene glycol-di-2-ethyl hexanoate; and dibutyl sebacate.
The roughness of the surface of a PVB sheet of the present invention is such that haze in a glass/PVB pre-press is low even if the PVB is used within 12 hours after it is stretched.
Surface roughness can be measured by conventional methods, and can be expressed by the term Rz. In a washboard PVB sheet of the present invention RZ is greater than about 30 micrometers, as determined by ISO R468. Preferably a washboard pattern of the present invention has a roughness of greater than about 35, more preferably greater than about 40 and most preferably from about 35 to about 100. In a herringbone pattern of the present invention, the RZ is less than about 35, preferably less than about 30, more preferably from about 15 to about 35, and most preferably from about 20 to about 30 micrometers. In a PVB
sheet of the present invention, the rough surface has a directional pattern, and the rough directional pattern is obtained without use of an embossing tool.
In another embodiment, the present invention is a laminate comprising at least one layer of PVB and at least one layer of glass, wherein the PVB layer is obtained by an extrusion process wherein a roughened PVB surface having / ...5 4a directionality is obtained without use of an embossing tool. The laminate is prepared according to conventional methods, wherein an assembly comprising at least one layer of PVB of the present invention is heated, and then de-aired under vacuum and at elevated temperature to form a pre-press. Alternatively, the laminate can be prepared by heating the assembly in an oven and then passing it through one or more pairs of nip rolls. The pre-press can be autoclaved according to conventional methods and conditions to yield a finished laminate article.
In still another embodiment, the present invention is a process for preparing a PVB sheet having a roughened surface having directionality imparted using a melt fracture extrusion process, without the aid of an embossing'tool.
The process comprises varying certain conditions and parameters in the extrusion process of PVB sheeting material. To prepare conventional PVB sheeting material, typically parameters can be varied to control surface pattern. Some parameters that can be varied are die body temperature and die gap, sheet caliper, lip stream pressure, lip gap, air gap, content of plasticizer, temperature of polymer, throughput of molten polymer per unit die width, and temperature of quench water. Other parameters can be varied as well. The directional patterns of the present invention can be obtained in the process of the present invention by varying the die pressure. Under certain die pressure operating conditions, a washboard pattern is one type of directional pattern that can be obtained on the PVB surface. For example, a washboard pattern can be obtained by operating at a die pressure of greater than 58 kg/ cm2 (5.69 MPa). A washboard pattern or surface, as the term is used herein, describes a surface having alternately high (1) and low (2) areas of elevation that form ridges (3), similar to the surface of a washboard. The ridges on a PVB surface of the present invention are nearly parallel to the cross-web direction of the interlayer as it is extruded, the cross-web direction being the direction perpendicular to that of the extrusion. Under certain other conditions of die pressure, a herringbone pattern can be obtained on the PVB
surface. A herringbone pattern is a second type of directional surface pattern that can be obtained in the process of the present invention by varying process conditions. For example, a herringbone pattern can be obtained by varying die pressure such that the pressure is below 37 kg/cm2 (3.63 MPa). The herringbone and washboard patterns are shown in Figure 1 and Figure 2, respectively. Other patterns can be obtained by varying process conditions, but the directional patterns of the present invention are controlled primarily by the die pressure.
Throughput (rate of polymer through the die)can be in the range of from about 600 to about 1000 kg per hr per meter, depending on the equipment being used.
EXAMPLES
The Examples and comparative examples herein are included for illustrative purposes only, and are not intended to limit the scope of the present invention.
In Examples 1-25, 100 parts of dry PVB flake of nominally 18-23% by weight of un-butyralated vinyl alcohol groups were mixed with 35-40 parts of tetraethylene glycol di-n-heptanoate plasticizer and one or more light stabilizers marketed under the tradename " Tinuvin" by Ciba-Geigy Co. and an antioxidant which were pre-mixed in the plasticizer continuously in a twin-screw extruder. The melt was forced through a slot die and formed a sheeting of 0.76 mm nominal thickness.
In addition, agents for modifying surface energy of the bulk interlayer and usual adjuvants such as antioxidants, colorants and ultraviolet absorbers which do not.
adversely affect the functioning of the surface energy modifying agent and adhesion control agent can be included in the PVB composition. The melt at the die is at approximately 200-220 C. The lips of the die are heated by injecting pressurized steam into cavities therein. The lip temperature is controlled by the pressure of the steam injected. One of the die lips is adjustable so that as it opens, the back-pressure in the die is decreased and vice versa. The position of this lip is computer-controlled, and a desired back-pressure in the die (die pressure) is used as input.
PVB sheeting having washboard or herringbone pattern was prepared on conventional extrusion equipment by varying the condition of die pressure. The same equipment was used for all of the examples. The conditions and results are given in the Table below.
Table Ex. Washboard (W) or Lip Steam Pressure No. Herringbone (H) or Die Pressure (kg/cm2) (kg/cm2) RZ (average) Random (R) (micrometers) 1 W 58.8 6.5 62.8 2 H 35.5 6.5 24.4 3 H 35.5 6.5 24.7 4 H 33.5 6.5 29.0 H 31.5 6.5 27.2 6 H 29.2 6.5 24.4 7 H 33.6 6.5 28.1 8 H 33.4 6.5 27.6 9 H 33.8 15 26.7 H 34.1 15 26.6 11 H 36.0 15 24.3 12 R 62.9 15 47.9 13 R 63.0 10 75.2 14 W 62.8 6.5 80.0 W 58.2 6.5 54.5 16 W 58.4 6.5 63.9 17 W 59.3 6.5 60.5 18 W 58.5 6.5 65.1 19 W 58.7 6.5 60.2 W 58.6 6.5 65.1 21 W 58.7 6.5 66.5 22 W 60.3 6.5 73.3 23 W 60.0 6.5 70.9 24 W 58.4 6.5 59.8 W 60.1 6.5 81.9 Comparative Example 26. Twenty full size windshields were prepared using a PVB interlayer commercially available from DuPont under the trade name Butacite BE-1120 with a random surface pattern generated by melt fracture. The die pressure used was 62.9 kg/cm2 (61.7 MPa), lip steam pressure was 15 kg/cm2 (14.7 MPa). The roughness in terms of Rz was 47.9 micrometers, but there was no directionality. The interlayer was shaped using typical shaping equipment, and the shaped interlayer was allowed to recover at about 15 C for 4 hours. The pre-presses were prepared using a commercial vacuum-bag system with approximately 5 minutes of vacuum at ambient temperature, and 10 minutes inside an oven in which the PVB temperature gradually rose to about 100 C at the end of that period. Ten of the pre-presses were very hazy, and were judged to be unusable (50% yield).
Comparative Example 27. Another twenty full size windshields were made of the same interlayer as in Comparative Example 26 except that the shaped interlayers had 8 hours of recovery after shaping. Five of the pre-presses were judged unusable (75% yield). This example shows that longer recovery time improves pre-press yield.
Example 28. Twenty windshields were prepared using the procedure in Comparative Example 26, except that the interlayer had washboard pattern, and Rz was 62.8 micrometer. It was made with die pressure of 58.8 kg/cm2 (57.7 MPa) and lip steam pressure of 6.5 kg/cm2 (6.4 MPa). The interlayer had 4 hours of recovery time after shaping before it was assembled. One of the twenty pre-presses was judged unusable (95% yield). The pre-press yield was much higher than that in Comparative Example 26 although the sheeting was rougher, leading one skilled in the art to suspect that the pre-press would be hazier.
Example 29. Twenty windshields were prepared as in Example 28, except that the interlayer had 8 hours of recovery time after shaping before it was assembled.
None of the twenty windshields was judged unusable (100% yield).
Comparative Example 27. Another twenty full size windshields were made of the same interlayer as in Comparative Example 26 except that the shaped interlayers had 8 hours of recovery after shaping. Five of the pre-presses were judged unusable (75% yield). This example shows that longer recovery time improves pre-press yield.
Example 28. Twenty windshields were prepared using the procedure in Comparative Example 26, except that the interlayer had washboard pattern, and Rz was 62.8 micrometer. It was made with die pressure of 58.8 kg/cm2 (57.7 MPa) and lip steam pressure of 6.5 kg/cm2 (6.4 MPa). The interlayer had 4 hours of recovery time after shaping before it was assembled. One of the twenty pre-presses was judged unusable (95% yield). The pre-press yield was much higher than that in Comparative Example 26 although the sheeting was rougher, leading one skilled in the art to suspect that the pre-press would be hazier.
Example 29. Twenty windshields were prepared as in Example 28, except that the interlayer had 8 hours of recovery time after shaping before it was assembled.
None of the twenty windshields was judged unusable (100% yield).
Claims (21)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A polyvinyl butyral sheet having a roughened directional surface pattern obtained by a melt fracture extrusion process without the use of an embossing tool, wherein the roughened directional surface pattern is a herringbone pattern obtained by using a die pressure of less than 37 kg/cm2.
2. The sheet of Claim 1 having an R z of greater than 35.
3. The sheet of Claim 1 having an R z of greater than 30.
4. The sheet of Claim 1 having an R z of from 15 to 35.
5. The sheet of Claim 1 having an R z of from 20 to 30.
6. A process for creating a directional pattern on a surface of a polyvinyl butyral sheet comprising the step: extruding molten polyvinyl butyral using a melt fracture extrusion process, wherein the pattern can be varied by varying the extrusion process parameters and wherein an embossing tool is not used, wherein the directional pattern is a herringbone pattern or washboard pattern, wherein the washboard pattern is created using a die pressure of greater than 58 kg/cm2, and wherein the herringbone pattern is created using a die pressure of less than 37 kg/cm2.
7. The process of Claim 6 wherein the lip steam pressure is below 15 kg/cm2(1.47 MPa) for the creation of the herringbone pattern.
8. A laminate comprising a polyvinyl butyral interlayer, wherein the interlayer is obtained from a polyvinyl butyral sheet having a roughened directional surface pattern obtained by extrusion of the sheet using a melt fracture process, wherein the roughened directional surface pattern is a herringbone pattern wherein the herringbone pattern is obtained by using a die pressure of less than 37 kg/cm2.
9. The laminate of Claim 8 wherein at least one layer is glass adhered to the polyvinyl butyral sheet.
10. The laminate of Claim 8 wherein the polyvinyl butyral sheet is adhered to at least two layers of glass.
11. The laminate of Claim 8 wherein at least one layer of an additional polymer is included in addition to the polyvinyl butyral sheet.
12. Use of a laminate as defined in Claim 8, 9, 10 or 11 in the manufacture of an article.
13. The use of Claim 12 wherein the article is a windshield, or automotive side-glass.
14. The use of Claim 12 wherein the article is a window, shelf, or architectural glass.
15. Use of a polyvinyl butyral sheet having a roughened directional surface pattern obtained by extrusion of the sheet using a melt fracture process, wherein the roughened directional surface pattern is a herringbone pattern wherein the herringbone pattern is obtained by using a die pressure of less than 37 kg/cm2, as an interlayer of a laminate.
16. The use of Claim 15 wherein at least one layer of the laminate is glass adhered to the polyvinyl butyral sheet.
17. The use of Claim 16 wherein the polyvinyl butyral sheet is adhered to at least two layers of glass.
18. The use of Claim 15 wherein at least one layer of an additional polymer is included in addition to the polyvinyl butyral sheet of the laminate.
19. An article obtained from a laminate as defined in Claim 8, 9, 10 or 11.
20. The article of Claim 19 wherein the article is a windshield, or automotive side-glass.
21. The article of Claim 19 wherein the article is a window, shelf, or architectural glass.
Applications Claiming Priority (3)
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| US19303900P | 2000-03-29 | 2000-03-29 | |
| US60/193,039 | 2000-03-29 | ||
| PCT/US2001/010023 WO2001072510A2 (en) | 2000-03-29 | 2001-03-29 | Glass/polyvinylbutyral laminates having directional surface patterns and a process for preparing same |
Publications (2)
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| CA2399724A1 CA2399724A1 (en) | 2001-10-04 |
| CA2399724C true CA2399724C (en) | 2010-12-21 |
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| CA2399724A Expired - Lifetime CA2399724C (en) | 2000-03-29 | 2001-03-29 | Glass/polyvinylbutyral laminates having directional surface patterns and a process for preparing same |
Country Status (8)
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| US (1) | US20030012964A1 (en) |
| EP (1) | EP1268196B2 (en) |
| JP (1) | JP4879438B2 (en) |
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| DE (1) | DE60105781T3 (en) |
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| WO (1) | WO2001072510A2 (en) |
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|---|---|---|---|---|
| US7351468B2 (en) * | 2000-10-26 | 2008-04-01 | E. I. Du Pont De Nemours And Company | Interlayers for laminated safety glass with superior de-airing and laminating properties and process for making the same |
| US20060263608A1 (en) * | 2002-08-14 | 2006-11-23 | Choi Chul W | Glass/polyvinylbutyral laminates having directional surface patterns and a process for preparing same |
| BE1015771A3 (en) | 2003-11-06 | 2005-08-02 | Kantoorinrichting Stulens N V | Rear screen. |
| JP2007514050A (en) * | 2003-12-15 | 2007-05-31 | イー・アイ・デュポン・ドウ・ヌムール・アンド・カンパニー | Method for preparing a polymer film useful for blocking transmission of near infrared light |
| US7678441B2 (en) | 2005-12-02 | 2010-03-16 | E.I. Du Pont De Nemours And Company | Interlayers for laminated safety glass with superior de-airing and laminating properties and process for making the same |
| AU2012201271B2 (en) * | 2007-04-13 | 2014-08-21 | Solutia Inc. | Multiple layer polymer interlayers having a melt fractured surface |
| US20080254302A1 (en) * | 2007-04-13 | 2008-10-16 | David Paul Bourcier | Multiple layer polymer interlayers having a melt fractured surface |
| US20080268204A1 (en) * | 2007-04-29 | 2008-10-30 | David Paul Bourcier | Multiple layer polymer interlayers having an embossed surface |
| AU2012201267B2 (en) * | 2007-04-29 | 2014-09-04 | Solutia Inc. | Multiple layer polymer interlayers having an embossed surface |
| FI123440B (en) * | 2008-10-31 | 2013-05-15 | Upm Kymmene Corp | Process for forming a wood composite product, wood composite product, and manufacturing device for a wood composite product |
| WO2012148368A2 (en) * | 2011-04-01 | 2012-11-01 | Aydeskin Mustafa | Printed and unprinted composite laminated glass and production method |
| US9574028B2 (en) | 2013-04-09 | 2017-02-21 | Solutia Inc. | Embossed polymer sheet |
| KR101547233B1 (en) * | 2013-11-18 | 2015-08-26 | 에스케이씨 주식회사 | Polyvinyl acetal sheet for use in connection of two glass plates, preparation method thereof and preparation method of glass plate laminate |
| US10350858B2 (en) | 2014-03-31 | 2019-07-16 | Sekisui Chemical Co., Ltd. | Interlayer film for laminated glass, and laminated glass |
| MX2017012977A (en) * | 2015-04-10 | 2018-02-01 | Sekisui Chemical Co Ltd | Interlayer for laminated glass, laminated glass, and production method for interlayer for laminated glass. |
| CN107848881B (en) * | 2015-07-31 | 2021-11-23 | 积水化学工业株式会社 | Interlayer film for laminated glass, method for producing interlayer film for laminated glass, and laminated glass |
| WO2020007610A1 (en) * | 2018-07-02 | 2020-01-09 | Saint-Gobain Glass France | Wedge-shaped multi-ply intermediate layer with acoustically damping properties |
| CN118119503A (en) * | 2021-10-19 | 2024-05-31 | 首诺公司 | Polymer interlayers having low mottle and reduced ice bloom defects |
Family Cites Families (8)
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|---|---|---|---|---|
| US3994654A (en) † | 1975-01-02 | 1976-11-30 | Monsanto Company | Die for extruding thermoplastic sheets |
| JPS60204643A (en) * | 1984-03-30 | 1985-10-16 | Sekisui Chem Co Ltd | Interlayer for sandwich glass |
| US4925725A (en) * | 1984-03-30 | 1990-05-15 | Sekisui Kagaku Kogyo Kabushiki Kaisha | Interlayer for laminated glass |
| US4654179A (en) * | 1985-07-02 | 1987-03-31 | Monsanto Company | Polyvinyl butyral sheet roughness control |
| JPH0735078B2 (en) * | 1989-03-31 | 1995-04-19 | 積水化学工業株式会社 | Method for producing embossed thermoplastic resin sheet |
| AU621471B2 (en) † | 1989-03-31 | 1992-03-12 | Sekisui Kagaku Kogyo Kabushiki Kaisha | A method for the manufacture of thermoplastic resin sheets |
| JPH02301417A (en) * | 1989-05-16 | 1990-12-13 | Shin Etsu Chem Co Ltd | Manufacture of surface-roughened polyvinyl butyral resin sheet |
| US5455103A (en) * | 1994-01-24 | 1995-10-03 | Monsanto Company | Rough-surfaced interlayer |
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2001
- 2001-03-29 DE DE60105781T patent/DE60105781T3/en not_active Expired - Lifetime
- 2001-03-29 EP EP01920860A patent/EP1268196B2/en not_active Expired - Lifetime
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- 2001-03-29 US US10/204,128 patent/US20030012964A1/en not_active Abandoned
- 2001-03-29 CA CA2399724A patent/CA2399724C/en not_active Expired - Lifetime
- 2001-03-29 AU AU2001247870A patent/AU2001247870B2/en not_active Ceased
- 2001-03-29 WO PCT/US2001/010023 patent/WO2001072510A2/en active IP Right Grant
- 2001-03-29 JP JP2001570445A patent/JP4879438B2/en not_active Expired - Fee Related
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| EP1268196A2 (en) | 2003-01-02 |
| EP1268196B2 (en) | 2009-09-30 |
| EP1268196B1 (en) | 2004-09-22 |
| JP2003528749A (en) | 2003-09-30 |
| AU2001247870B2 (en) | 2005-09-15 |
| WO2001072510A2 (en) | 2001-10-04 |
| JP4879438B2 (en) | 2012-02-22 |
| DE60105781D1 (en) | 2004-10-28 |
| WO2001072510A3 (en) | 2002-03-07 |
| US20030012964A1 (en) | 2003-01-16 |
| AU4787001A (en) | 2001-10-08 |
| CA2399724A1 (en) | 2001-10-04 |
| DE60105781T3 (en) | 2010-05-06 |
| DE60105781T2 (en) | 2005-10-13 |
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